Depletion of Dissolved Oxygen in the Closed, Stratified Estuary of the Russian River, California
Bibliographic record
Abstract
The Russian River Estuary in Sonoma County, California is a threatened ecosystem that provides an important habitat for salmonids (e.g. Coho salmon, Chinook salmon, and Steelhead trout) during several life stages. Periodically, the tidal inlet of the estuary is blocked when wave action overcomes tidal and river flows, creating a sand barrier. The resulting cessation of tidal mixing in the estuary causes persistent water column stratification between saline bottom‐waters and fresh surface waters. The bottom‐waters are then isolated from atmospheric oxygen inputs and dissolved oxygen declines, reducing available habitat for salmonids. To examine this problem, we compared time‐series data of dissolved oxygen levels during past closure events with directly‐measured biochemical oxygen demand (BOD) levels. We found that bottom‐water dissolved oxygen concentrations typically reached hypoxia (<3 mg/L) in lessthan four days. BOD levels in the estuary were highest in bottom‐waters, especially in deep scour‐holes upstream where water is trapped and riverine organic matter accumulates. Water column BOD due to the decomposition of organic matter accounted for a majority of observed oxygen consumption rates. We found little evidence of re‐oxygenation of the bottom‐water while the inlet remained closed (typically periods of less than 10 days). Although further study is required to determine oxygen dynamics throughout a longer closure period, the persistence of bottomwater hypoxia during the events we examined is an important consideration for estuary and watershed management.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".